Dental metal alloys



Patented Feb. 1, 1949 nm'ro l Claim.

There are two kinds of metal alloys for dental purposes, those rolled into sheet material and used e. g. for making crowns, and those cast for making bridges or inlays. This invention is concerned with the utilisation of the waste obtained from the sheet material. The sheet material consists as a rule of palladium, gold and silver in proportions of about 25-39%, -10% and 60-70% respectively and has a rather high melting point of about 1206-1300 C. Such an alloy can be sin lted by means of a hydrogen-oxygen flame only, which is not always available.

As is known, there occurs in dental technics a considerable amount or" waste of the said rolled alloy, which the dentists, however, are unable to smelt and use again with the burners at their disposal, and thus are forced to deliver them to metal refineries.

This diificulty is alleviated by the present invention, according to which a new alloy has been prepared which itself is smeltable at about 1000 C., in which, when molten, the said waste material added in the proportion from two to one .to one part of the new alloy easily dissolves and which together give an ultimate alloy which is suitable for dental castings, as e. g. used for clasps, bridges and hard inlays, and has a M. P. of 1000-1100 C. p

The composition of the new alloy which I have found most suitable is:

Metal Au Pt Ni Zn Ag Pd Cu Parts by weight 1 V 1 1 1 1o 13 21 with white gold sheet waste is:

Metal Au Pt Zn Ag Pd Cu Ni Parts by Weight 30 1 1 3 4 1 Here too the M. P. of the new alloy is about 1000 C., the proportion of mixture is from two to one of the waste to one part of the alloy, and the M. P. of the ultimate alloy is 1000-1100 C.

The new alloys can be prepared in different In Palestine June 26, 19%

(Cl. YE-=- 3i) ways. One may begin with heating a component element of a high melting point and then add in the course of the smelting process elements of lower melting points at the same time lowering the temperature. Or conversely, one can start with heating an element with a low melting point and then add elements of high melting points, at the same time increasing the temperature. The new alloys can be produced on an industrial scale and sold to dentists. Instead of ZN may be added to the alloy in the same proportion Cd, Sn or Bi.

The following examples will illustrate the use of the new alloys:

10 grams of ordinary dental sheet metal waste not meltable at a temperature of 10001100 is added to a molten alloy being 10 grams of the composition Parts Pt, Au, Ni, Zn, each 1 Ag 10 Pd 13 Cu 21 The ten grams of waste easily dissolve in the molten alloy at the above temperature.

10 grams of white gold sheet waste not meltable at a temperature of 1000-1100 C. are added to a molten alloy being 10 grams of the composition.

Parts Pt, Zn, Ni, each 1 Au 30 Ag 3 Pa 4 Cu 10 REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS 7 Country Date Switzerland May 16, 1942 OTHER REFERENCES Refining Precious Metal Wastes, by Hoke, 1940, pages 133 and 134.

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